how to set ulimit file descriptor on docker container the image tag is phusion baseimage-docker

Question

I need to set the file descriptor limit correctly on the docker container  I connect to container with ssh  https   github com phusion baseimage-docker   Already tried    edit limits conf  the container ignore this file  upstart procedure found at https   coderwall com p myodcq but this docker image has different kind of init process   runit  I tried to modify configuration of pam library in  etc pam d try to enabled pam for ssh  in sshd config   The output it always the same    bash  ulimit  open files  cannot modify limit  Operation not permitted

User · Answer

After some searching I found this on a Google groups discussion:

docker currently inhibits this capability for enhanced safety.

That is because the ulimit settings of the host system apply to the docker container. It is regarded as a security risk that programs running in a container can change the ulimit settings for the host.

The good news is that you have two different solutions to choose from.

Remove sys_resource from lxc_template.go and recompile docker. Then you'll be able to set the ulimit as high as you like.

or

Stop the docker demon. Change the ulimit settings on the host. Start the docker demon. It now has your revised limits, and its child processes as well.

I applied the second method:

sudo service docker stop;
changed the limits in /etc/security/limits.conf
reboot the machine
run my container
run ulimit -a in the container to confirm the open files limit has been inherited.

See: https://groups.google.com/forum/#!searchin/docker-user/limits/docker-user/T45Kc9vD804/v8J_N4gLbacJ

User · Answer

For boot2docker  we can set it on  var lib boot2docker profile  for instance   ulimit -n 2018  Be warned not to set this limit too high as it will slow down apt-get  See bug  1332440  I had it with debian jessie

User · Answer

Actually  I have tried the above answer  but it did not seem to work    To get my containers to acknowledge the ulimit change  I had to update the docker conf file before starting them     sudo service docker stop   sudo bash -c  echo   limit nofile 262144 262144    gt  gt   etc init docker conf    sudo service docker start

User · Answer

Here is what I did   set  ulimit -n 32000 in the file  etc init d docker  and restart the docker service  docker run -ti node latest  bin bash  run this command to verify  user 4d04d06d5022    ulimit -a  should see this in the result  open files                       -n  32000   user ip ec2-user   docker run -ti node  bin bash user 4d04d06d5022    ulimit -a core file size           blocks  -c  0 data seg size            kbytes  -d  unlimited scheduling priority              -e  0 file size                blocks  -f  unlimited pending signals                  -i  58729 max locked memory        kbytes  -l  64 max memory size          kbytes  -m  unlimited open files                       -n  32000 pipe size             512 bytes  -p  8 POSIX message queues      bytes  -q  819200 real-time priority               -r  0 stack size               kbytes  -s  10240 cpu time                seconds  -t  unlimited max user processes               -u  58729 virtual memory           kbytes  -v  unlimited file locks                       -x  unlimited

User · Answer

If using the docker-compose file  Based on docker compose version 2 x We can set like as below  by overriding the default config   ulimits    nproc  65535   nofile      soft  26677     hard  46677   https   docs docker com compose compose-file

User · Answer

The docker run command has a --ulimit flag you can use this flag to set the open file limit in your docker container    Run the following command when spinning up your container to set the open file limit   docker run --ulimit nofile  lt softlimit gt   lt hardlimit gt  the first value before the colon indicates the soft file limit and the value after the colon indicates the hard file limit  you can verify this by running your container in interactive mode and executing the following command in your containers shell ulimit -n  PS  check out this blog post for more clarity

User · Answer

The latest docker supports setting ulimits through the command line and the API  For instance  docker run takes --ulimit  lt type gt   lt soft gt   lt hard gt  and there can be as many of these as you like  So  for your nofile  an example would be --ulimit nofile 262144 262144

User · Answer

I have tried many options and unsure as to why a few solutions suggested above work on one machine and not on others   A solution that works and that is simple and can work per container is   docker run --ulimit memlock 819200000 819200000 -h  lt docker host name gt  --name current -v  home user home  user home -i -d -t docker user name image name

[docker] how to set ulimit / file descriptor on docker container the image tag is phusion/baseimage-docker

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